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<pre><span class="comment"> /****************************************************************************
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 ** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
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 #include &quot;interfaces.h&quot;
 #include &quot;mainwindow.h&quot;
 #include &quot;paintarea.h&quot;
 #include &quot;plugindialog.h&quot;

 #include &lt;QPluginLoader&gt;
 #include &lt;QTimer&gt;

 #include &lt;QScrollArea&gt;
 #include &lt;QMessageBox&gt;
 #include &lt;QActionGroup&gt;
 #include &lt;QAction&gt;
 #include &lt;QMenu&gt;
 #include &lt;QMenuBar&gt;
 #include &lt;QFileDialog&gt;
 #include &lt;QColorDialog&gt;
 #include &lt;QInputDialog&gt;
 #include &lt;QApplication&gt;

 MainWindow::MainWindow() :
     paintArea(new PaintArea),
     scrollArea(new QScrollArea)
 {
     scrollArea-&gt;setBackgroundRole(QPalette::Dark);
     scrollArea-&gt;setWidget(paintArea);
     setCentralWidget(scrollArea);

     createActions();
     createMenus();
     loadPlugins();

     setWindowTitle(tr(&quot;Plug &amp; Paint&quot;));

     if (!brushActionGroup-&gt;actions().isEmpty())
         brushActionGroup-&gt;actions().first()-&gt;trigger();

     QTimer::singleShot(500, this, SLOT(aboutPlugins()));
 }

 void MainWindow::open()
 {
     const QString fileName = QFileDialog::getOpenFileName(this,
                                                           tr(&quot;Open File&quot;),
                                                           QDir::currentPath());
     if (!fileName.isEmpty()) {
         if (!paintArea-&gt;openImage(fileName)) {
             QMessageBox::information(this, tr(&quot;Plug &amp; Paint&quot;),
                                      tr(&quot;Cannot load %1.&quot;).arg(fileName));
             return;
         }
         paintArea-&gt;adjustSize();
     }
 }

 bool MainWindow::saveAs()
 {
     const QString initialPath = QDir::currentPath() + &quot;/untitled.png&quot;;

     const QString fileName = QFileDialog::getSaveFileName(this, tr(&quot;Save As&quot;),
                                                           initialPath);
     if (fileName.isEmpty()) {
         return false;
     } else {
         return paintArea-&gt;saveImage(fileName, &quot;png&quot;);
     }
 }

 void MainWindow::brushColor()
 {
     const QColor newColor = QColorDialog::getColor(paintArea-&gt;brushColor());
     if (newColor.isValid())
         paintArea-&gt;setBrushColor(newColor);
 }

 void MainWindow::brushWidth()
 {
     bool ok;
     const int newWidth = QInputDialog::getInteger(this, tr(&quot;Plug &amp; Paint&quot;),
                                                   tr(&quot;Select brush width:&quot;),
                                                   paintArea-&gt;brushWidth(),
                                                   1, 50, 1, &amp;ok);
     if (ok)
         paintArea-&gt;setBrushWidth(newWidth);
 }

 void MainWindow::changeBrush()
 {
     QAction *action = qobject_cast&lt;QAction *&gt;(sender());
     BrushInterface *iBrush = qobject_cast&lt;BrushInterface *&gt;(action-&gt;parent());
     const QString brush = action-&gt;text();

     paintArea-&gt;setBrush(iBrush, brush);
 }

 void MainWindow::insertShape()
 {
     QAction *action = qobject_cast&lt;QAction *&gt;(sender());
     ShapeInterface *iShape = qobject_cast&lt;ShapeInterface *&gt;(action-&gt;parent());

     const QPainterPath path = iShape-&gt;generateShape(action-&gt;text(), this);
     if (!path.isEmpty())
         paintArea-&gt;insertShape(path);
 }

 void MainWindow::applyFilter()
 {
     QAction *action = qobject_cast&lt;QAction *&gt;(sender());
     FilterInterface *iFilter =
             qobject_cast&lt;FilterInterface *&gt;(action-&gt;parent());

     const QImage image = iFilter-&gt;filterImage(action-&gt;text(), paintArea-&gt;image(),
                                               this);
     paintArea-&gt;setImage(image);
 }

 void MainWindow::about()
 {
    QMessageBox::about(this, tr(&quot;About Plug &amp; Paint&quot;),
             tr(&quot;The &lt;b&gt;Plug &amp; Paint&lt;/b&gt; example demonstrates how to write Qt &quot;
                &quot;applications that can be extended through plugins.&quot;));
 }

 void MainWindow::aboutPlugins()
 {
     PluginDialog dialog(pluginsDir.path(), pluginFileNames, this);
     dialog.exec();
 }

 void MainWindow::createActions()
 {
     openAct = new QAction(tr(&quot;&amp;Open...&quot;), this);
     openAct-&gt;setShortcut(tr(&quot;Ctrl+O&quot;));
     connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

     saveAsAct = new QAction(tr(&quot;&amp;Save As...&quot;), this);
     saveAsAct-&gt;setShortcut(tr(&quot;Ctrl+S&quot;));
     connect(saveAsAct, SIGNAL(triggered()), this, SLOT(saveAs()));

     exitAct = new QAction(tr(&quot;E&amp;xit&quot;), this);
     exitAct-&gt;setShortcut(tr(&quot;Ctrl+Q&quot;));
     connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

     brushColorAct = new QAction(tr(&quot;&amp;Brush Color...&quot;), this);
     connect(brushColorAct, SIGNAL(triggered()), this, SLOT(brushColor()));

     brushWidthAct = new QAction(tr(&quot;&amp;Brush Width...&quot;), this);
     connect(brushWidthAct, SIGNAL(triggered()), this, SLOT(brushWidth()));

     brushActionGroup = new QActionGroup(this);

     aboutAct = new QAction(tr(&quot;&amp;About&quot;), this);
     connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

     aboutQtAct = new QAction(tr(&quot;About &amp;Qt&quot;), this);
     connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));

     aboutPluginsAct = new QAction(tr(&quot;About &amp;Plugins&quot;), this);
     connect(aboutPluginsAct, SIGNAL(triggered()), this, SLOT(aboutPlugins()));
 }

 void MainWindow::createMenus()
 {
     fileMenu = menuBar()-&gt;addMenu(tr(&quot;&amp;File&quot;));
     fileMenu-&gt;addAction(openAct);
     fileMenu-&gt;addAction(saveAsAct);
     fileMenu-&gt;addSeparator();
     fileMenu-&gt;addAction(exitAct);

     brushMenu = menuBar()-&gt;addMenu(tr(&quot;&amp;Brush&quot;));
     brushMenu-&gt;addAction(brushColorAct);
     brushMenu-&gt;addAction(brushWidthAct);
     brushMenu-&gt;addSeparator();

     shapesMenu = menuBar()-&gt;addMenu(tr(&quot;&amp;Shapes&quot;));

     filterMenu = menuBar()-&gt;addMenu(tr(&quot;&amp;Filter&quot;));

     menuBar()-&gt;addSeparator();

     helpMenu = menuBar()-&gt;addMenu(tr(&quot;&amp;Help&quot;));
     helpMenu-&gt;addAction(aboutAct);
     helpMenu-&gt;addAction(aboutQtAct);
     helpMenu-&gt;addAction(aboutPluginsAct);
 }

 void MainWindow::loadPlugins()
 {
     foreach (QObject *plugin, QPluginLoader::staticInstances())
         populateMenus(plugin);

     pluginsDir = QDir(qApp-&gt;applicationDirPath());

 #if defined(Q_OS_WIN)
     if (pluginsDir.dirName().toLower() == &quot;debug&quot; || pluginsDir.dirName().toLower() == &quot;release&quot;)
         pluginsDir.cdUp();
 #elif defined(Q_OS_MAC)
     if (pluginsDir.dirName() == &quot;MacOS&quot;) {
         pluginsDir.cdUp();
         pluginsDir.cdUp();
         pluginsDir.cdUp();
     }
 #endif
     pluginsDir.cd(&quot;plugins&quot;);

     foreach (QString fileName, pluginsDir.entryList(QDir::Files)) {
         QPluginLoader loader(pluginsDir.absoluteFilePath(fileName));
         QObject *plugin = loader.instance();
         if (plugin) {
             populateMenus(plugin);
             pluginFileNames += fileName;
         }
     }

     brushMenu-&gt;setEnabled(!brushActionGroup-&gt;actions().isEmpty());
     shapesMenu-&gt;setEnabled(!shapesMenu-&gt;actions().isEmpty());
     filterMenu-&gt;setEnabled(!filterMenu-&gt;actions().isEmpty());
 }

 void MainWindow::populateMenus(QObject *plugin)
 {
     BrushInterface *iBrush = qobject_cast&lt;BrushInterface *&gt;(plugin);
     if (iBrush)
         addToMenu(plugin, iBrush-&gt;brushes(), brushMenu, SLOT(changeBrush()),
                   brushActionGroup);

     ShapeInterface *iShape = qobject_cast&lt;ShapeInterface *&gt;(plugin);
     if (iShape)
         addToMenu(plugin, iShape-&gt;shapes(), shapesMenu, SLOT(insertShape()));

     FilterInterface *iFilter = qobject_cast&lt;FilterInterface *&gt;(plugin);
     if (iFilter)
         addToMenu(plugin, iFilter-&gt;filters(), filterMenu, SLOT(applyFilter()));
 }

 void MainWindow::addToMenu(QObject *plugin, const QStringList &amp;texts,
                            QMenu *menu, const char *member,
                            QActionGroup *actionGroup)
 {
     foreach (QString text, texts) {
         QAction *action = new QAction(text, plugin);
         connect(action, SIGNAL(triggered()), this, member);
         menu-&gt;addAction(action);

         if (actionGroup) {
             action-&gt;setCheckable(true);
             actionGroup-&gt;addAction(action);
         }
     }
 }</pre>
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